The Calculation Of Motor Structure System Vibration With Finite Element Method

With the devolpment of motor industry, the requirement for motor have exigent,ande motor vibration problem is becoming more ande more important. In this paper,the commercial software ANSYS is been used on motor structure finite elementanalysis, a detailed study has been made on the motor rotor modal analysis, base feeteffects on motor modal as well as base feet static analysis, at the same time the modelresults comparied with experimental results turns out that the models are reliable.Research contents and results are as follows:1. ANSYS is used to establish the model of rotor and the experimental results arecompared with the simulation calculations, put forward the concept of soft layer tosimulate the gap between rotor core and rotor shaft of the rotor shaft and a rotor corerigidity effect, makes the rotor shaft and a rotor iron core rigidity continuous,discussed the soft layer with different stiffness degree coefficient and thicknessinfluence on the natural frequency of the rotor in detail. Research shows that when thesoft layer elastic modulus is bigger than1.78×109Pa, the first six will not change, asthe elastic modulus reduce, rotor’s vibration modes will change. The thickness of softlayer has small influents on the rotor modal change.2. ANSYS is used to establish the model of foundation and the experimentalresults are compared with the simulation calculations, the influence of the length ofthe root inclined board and the elastic modulus of soft layer which simulates theconnection between the ground and the root has been discussed. The research showsthat, along with the inclined board length changes, the first order and the sixth orderof natural frequency will have a fluctuation change, the other orders of the naturalfrequency decreases linearly; with the change of foundation elastic modulus, motorfrequency will change as well, when the elastic modulus is1.78×109Pa, motor modewill change, the vibration of the motor is smooth, the foundation vibration increases.3. ANSYS is been used to establish the model of the foot of foundation, given aexternal force, the stiffness of foundation in X, Y, Z directions is calculated，and thelaw of the foot of foundation stiffness change with the foot modulus and thicknesschange is been discussed. The research shows that the foot of foundation stiffnesswith the base foundation elastic modulus and thickness is linear change.